/Engine/Source/Runtime/Engine/Classes/Kismet/KismetMathLibrary.h
Example: ChildOffset = MakeRelativeTransform(Child.GetActorTransform(), Parent.GetActorTransform()) This computes the relative transform of the Child from the Parent.
The new relative transform
static FTransform MakeRelativeTransform ( const FTransform & A, const FTransform & RelativeTo )